The focus of this study is on the development of a state-of-the-art single-wheel roller rig for studying contact mechanics and dynamics in railroad applications. The use of indoor-based simulation tools has become a mainstay in vehicle testing for the automotive and railroad industries. In contrast to field-testing, roller rigs offer a controlled laboratory environment that can provide a successful path for obtaining data on the mechanics and dynamics of railway systems for a variety of operating conditions. The idea to develop a laboratory test rig started from the observation that there is a need for better-developed testing fixtures capable of accurately explaining the complex physics of wheel-rail contact toward designing faster, safer, and more efficient railway systems. A review of current roller rigs indicated that many desired functional requirements for studying contact mechanics currently are not available. Thus, the Virginia Tech Railway Technologies Laboratory (RTL) has embarked on a mission to develop a state-of-the-art testing facility that will allow experimental testing of contact mechanics in a dynamic, controlled, and consistent manner. VT roller rig will allow for closely replicating the boundary conditions of railroad wheel-rail contact via actively controlling all the wheel-rail interface degrees of freedom: cant angle, angle of attack, and lateral displacement. Two sophisticated independent drivelines are configured to precisely control the rotational speed of the wheels, and therefore their relative slip or creepage. A novel force measurement system, suitable for steel on steel contact, is configured to precisely measure the contact forces and moments at the contact patch. The control architecture is developed based on the SynqNet data acquisition system offered by Kollmorgen, the motors supplier. SynqNet provides a unified communication protocol between actuators, drives, and data acquisition system, hence eliminating data conversion among them. Various design analysis indicates that the rig successfully meets the set requirements: additional accuracy in measurements, and better control on the design of experiments. The test results show that the rig is capable of conducting various contact mechanics studies aimed for advancing the existing art. Beyond developing the experimental testing fixture for studying contact mechanics, this study provides a comprehensive review of the contact models. It discusses the simplifying assumptions for developing the models, compares the models functionality, and highlights the open areas that require further experimental and theoretical research. In addition, a multi-body dynamic model of the entire rig, using software package SIMPACK, is developed for conducting modal analysis of the rig and evaluating the performance of the rig's components. A MATLAB routine is also developed that provides a benchmark for developing creep curves from measurements of the rig and comparing them with existing creep curves. / Ph. D.

Diese Arbeit ist das Ergebnis von mehr als 35 Jahren Erfahrung mit Hochspannungsfreileitungen, 25 Jahre davon sind durch die intensive Beschäftigung mit Silikonverbundisolatoren stark geprägt worden. Verbundisolatoren werden inzwischen als gleichwertige Alternative zu Porzellan- und Glasisolatoren anerkannt und weltweit in großen Stückzahlen eingesetzt. Durch die Verschiedenartigkeit seiner Komponenten ist die Wechselwirkung zwischen mechanischer und elektrischer Integrität bei einem Verbundisolator von großer Bedeutung. Man denke z.B. an die Auswirkung von Rissen im glasfaserverstärkten Kern, die durch unzureichende mechanische Auslegung entstehen und Teilentladungen bzw. im schlimmsten Fall einen inneren Durchschlag verursachen können. In diesem Sinne untersucht diese Arbeit , nach einer kurzen Einleitung, die verschiedenen Bauarten von Verbundisolatoren, d.h. Verbundlangstäbe, Verbundstützer, Isoliertraversen für Kompaktleitungen und Phasenabstandshalter; insbesondere für letztere werden neue Erkenntnisse zu deren mechanischen Bemessung hier erstmalig veröffentlicht.:1 Einleitung 1.1 Vorteile und Entwicklung von Verbundisolatoren 1.2 Erfahrungen mit Verbundisolatoren 1.3 Einsatz von Verbundisolatoren in Hochspannungsfreileitungen 1.4 Einsatz von Verbundisolatoren bei elektrischen Apparaten und Freiluftschaltanlagen. 1.5 Stand der Normung 2 Verbundlangstabisolatoren 2.1 Anwendungen von Verbundlangstabisolatoren 2.2 Das Verhalten von Verbundlangstabisolatoren unter mechanischer Beanspruchung 2.2.1 Die Dauerstandfestigkeit von Verbundlangstabisolatoren 2.2.1.1 Die Dauerkraftkurve von Verbundisolatoren nach IEC 61109/92 2.2.1.2 Mechanisches Modell für das Langzeitverhalten von Verbundisolatoren 2.3 Verhalten von Verbundlangstabisolatoren bei dynamischer Belastung 2.4 Auslegung und Montage von Endarmaturen für Verbundlangstäbe 2.4.1 Entwicklung und Stand der Technik der Metallarmaturen 2.4.2 Grundsätzliche Überlegungen zu der Auslegung von Pressarmaturen 2.4.3 Montagetechnik von Pressarmaturen 2.4.4 Berechnungssystematik 2.4.5 Einfache analytische Methode 2.4.6 Fortgeschrittene analytische Methode 2.4.6.1 Verpressung 2.4.6.2 Relaxation 2.4.6.3 Zugbelastung/Pull-out 2.4.7 Numerische Simulation 2.4.7.1 Finite Elemente Modell 2.4.7.2 Rechenergebnisse der Simulation 2.4.7.3 Ergebnisse der numerischen Versagenssimulation 2.4.7.4 Versuchsergebnisse 2.4.7.5 Sensitivitätsanalyse 2.5 Formelzeichen und Abkürzungen 3 Verbundstützisolatoren 3.1 Wesentliche Eigenschaften 3.2 Anwendungen von Verbundstützisolatoren 3.3 Das Verhalten von Verbundstützisolatoren unter Biegung 3.3.1 Allgemeines 3.3.2 Einführung einer Schadensgrenze (damage limit) 3.3.2.1 Versuche zur Bestimmung der Schadensgrenze 3.3.2.2 Versuch zur Bestimmung der maximalen Betriebsbiegelast (MDCL) 3.3.2.3 Bestimmung der MDCL und der SCL im gleichen Versuch 3.4 Herstellerangaben zum SCL/MDCL Konzept 3.5 Das sichere Verhalten beim Versagen von Verbundstützern (safe failure mode) 3.6 Kombinierte Belastungen 3.6.1 Lastdiagramme 3.6.2 Beispiele 3.6.2.1 Horizontale Lage des Isolators 3.6.2.2 Isolator bildet einen Winkel von β = 15° zur Horizontalen 3.6.3 Computersimulation 3.6.4 Versuche 3.7 Dynamische Belastungen 3.7.1 Prüflinge 3.7.2 Prüfverfahren 3.7.3 Versuchsergebnisse 3.8 Konstruktive Anforderungen der Endarmaturen 3.9 Analytische Berechnungsmethoden 3.9.1 Einfache analytische Methode 3.9.2 Fortgeschrittene analytische Methode 3.9.2.1 Radiale Druckspannung an der Öffnung der Metallarmatur 3.9.2.2 Axialspannung im GFK-Stab innerhalb der Metallarmatur 3.9.2.3 Schubspannung in der neutralen Achse des Stabes 3.10 Numerische Simulation 3.10.1 Finite Elemente Modell 3.10.2 Versuchsanordnung 3.11 Das Versagensverhalten von Verbundstützisolatoren 3.12 Sensitivitätsanalyse 3.13 Formelzeichen und Abkürzungen 4 Isoliertraversen für Kompaktleitungen 4.1 Einleitung 4.2 Grundsätze der Kompaktierung 4.2.1 Einfluss der Seilaufhängung auf das Mastbild 4.2.2 Möglichkeiten der Leitungskompaktierung 4.2.2.1 V-Ketten 4.2.2.2 Leitungsstützer (horizontal) 4.2.2.3 Abgehängter Leitungsstützer 4.2.2.4 Isoliertraverse 4.3 Die mechanische Auslegung von Isoliertraversen 4.3.1 Die starr gelagerte Isoliertraverse 4.3.2 Die gelenkig gelagerte Isoliertraverse (horizontal-V) 4.3.3 Dynamische Belastungen 4.3.4 Stabilitätsuntersuchungen 4.4 Innovative Anwendungen von Kompaktleitungen 4.4.1 420 kV Leitung mit Hohlkörperisolatoren in der Schweiz 4.4.2 Notgestänge mit Verbundisolatoren 4.4.3 Erste 420 kV Doppelleitung mit Volkernverbundtraversen 4.5 Formelzeichen und Abkürzungen 5 Phasenabstandshalter 5.1 Einleitung 5.2 CIGRE Umfrage 5.2.1 Auswertung Fragebogen 5.2.2 Betriebserfahrungen 5.3 Anschlusstechnik 5.4 Mechanische Auslegung von Phasenabstandshaltern 5.4.1 Galloping 5.4.1.1 Galloping Amplituden 5.4.1.2 Bauweisen 5.4.1.3 Einbauempfehlungen 5.4.1.4 Belastungen der PAH durch Galloping 5.4.2 Abwurf von Eislasten 5.4.2.1 Stosskräfte auf die PAH . 5.4.3 Elektrodynamische Kurzschlusskräfte 5.4.4 Das Knickverhalten von Phasenabstandshaltern 5.5 Elektrische Auslegung von Phasenabstandshaltern 5.5.1 Mindestlänge 5.5.2 Koronaeffekte 5.5.3 Verschmutzung 5.6 Anwendungen 5.6.1 Kompaktleitung für Mittelspannung 5.6.2 Phasenabstandshalter gegen Seiltanzen durch Eisabwurf 5.6.3 Der Tennisschlägermast 5.7 Formelzeichen und Abkürzungen 6 Ausblick 7 Anhang IEC Normen betreffend Verbundisolatoren 8 Quellenverzeichnis. / This work is the result of more than 35 years of experience with high-voltage overhead lines, 25 years of which have been devoted to silicone composite insulators. Composite insulators are nowadays regarded as an equivalent alternative to porcelain and glass insulators and are used worldwide in large quantities. Due to the diverse properties of the individual insulator components, the interaction between mechanical and electrical integrity in a composite insulator is of paramount importance. For example, cracks in the glass fiber reinforced core, caused by poor mechanical design, can lead to partial discharges and in the worst case to a catastrophic internal electrical breakdown ('flashunder'). In this sense this publication examines, after a short introduction, the different types of composite insulators, i.e. composite long rods, composite posts, insulating cross-arms for compact lines and phase-to-phase spacers; for the latter a new mechanical design concept considering large deflection theory is presented here for the first time.:1 Einleitung 1.1 Vorteile und Entwicklung von Verbundisolatoren 1.2 Erfahrungen mit Verbundisolatoren 1.3 Einsatz von Verbundisolatoren in Hochspannungsfreileitungen 1.4 Einsatz von Verbundisolatoren bei elektrischen Apparaten und Freiluftschaltanlagen. 1.5 Stand der Normung 2 Verbundlangstabisolatoren 2.1 Anwendungen von Verbundlangstabisolatoren 2.2 Das Verhalten von Verbundlangstabisolatoren unter mechanischer Beanspruchung 2.2.1 Die Dauerstandfestigkeit von Verbundlangstabisolatoren 2.2.1.1 Die Dauerkraftkurve von Verbundisolatoren nach IEC 61109/92 2.2.1.2 Mechanisches Modell für das Langzeitverhalten von Verbundisolatoren 2.3 Verhalten von Verbundlangstabisolatoren bei dynamischer Belastung 2.4 Auslegung und Montage von Endarmaturen für Verbundlangstäbe 2.4.1 Entwicklung und Stand der Technik der Metallarmaturen 2.4.2 Grundsätzliche Überlegungen zu der Auslegung von Pressarmaturen 2.4.3 Montagetechnik von Pressarmaturen 2.4.4 Berechnungssystematik 2.4.5 Einfache analytische Methode 2.4.6 Fortgeschrittene analytische Methode 2.4.6.1 Verpressung 2.4.6.2 Relaxation 2.4.6.3 Zugbelastung/Pull-out 2.4.7 Numerische Simulation 2.4.7.1 Finite Elemente Modell 2.4.7.2 Rechenergebnisse der Simulation 2.4.7.3 Ergebnisse der numerischen Versagenssimulation 2.4.7.4 Versuchsergebnisse 2.4.7.5 Sensitivitätsanalyse 2.5 Formelzeichen und Abkürzungen 3 Verbundstützisolatoren 3.1 Wesentliche Eigenschaften 3.2 Anwendungen von Verbundstützisolatoren 3.3 Das Verhalten von Verbundstützisolatoren unter Biegung 3.3.1 Allgemeines 3.3.2 Einführung einer Schadensgrenze (damage limit) 3.3.2.1 Versuche zur Bestimmung der Schadensgrenze 3.3.2.2 Versuch zur Bestimmung der maximalen Betriebsbiegelast (MDCL) 3.3.2.3 Bestimmung der MDCL und der SCL im gleichen Versuch 3.4 Herstellerangaben zum SCL/MDCL Konzept 3.5 Das sichere Verhalten beim Versagen von Verbundstützern (safe failure mode) 3.6 Kombinierte Belastungen 3.6.1 Lastdiagramme 3.6.2 Beispiele 3.6.2.1 Horizontale Lage des Isolators 3.6.2.2 Isolator bildet einen Winkel von β = 15° zur Horizontalen 3.6.3 Computersimulation 3.6.4 Versuche 3.7 Dynamische Belastungen 3.7.1 Prüflinge 3.7.2 Prüfverfahren 3.7.3 Versuchsergebnisse 3.8 Konstruktive Anforderungen der Endarmaturen 3.9 Analytische Berechnungsmethoden 3.9.1 Einfache analytische Methode 3.9.2 Fortgeschrittene analytische Methode 3.9.2.1 Radiale Druckspannung an der Öffnung der Metallarmatur 3.9.2.2 Axialspannung im GFK-Stab innerhalb der Metallarmatur 3.9.2.3 Schubspannung in der neutralen Achse des Stabes 3.10 Numerische Simulation 3.10.1 Finite Elemente Modell 3.10.2 Versuchsanordnung 3.11 Das Versagensverhalten von Verbundstützisolatoren 3.12 Sensitivitätsanalyse 3.13 Formelzeichen und Abkürzungen 4 Isoliertraversen für Kompaktleitungen 4.1 Einleitung 4.2 Grundsätze der Kompaktierung 4.2.1 Einfluss der Seilaufhängung auf das Mastbild 4.2.2 Möglichkeiten der Leitungskompaktierung 4.2.2.1 V-Ketten 4.2.2.2 Leitungsstützer (horizontal) 4.2.2.3 Abgehängter Leitungsstützer 4.2.2.4 Isoliertraverse 4.3 Die mechanische Auslegung von Isoliertraversen 4.3.1 Die starr gelagerte Isoliertraverse 4.3.2 Die gelenkig gelagerte Isoliertraverse (horizontal-V) 4.3.3 Dynamische Belastungen 4.3.4 Stabilitätsuntersuchungen 4.4 Innovative Anwendungen von Kompaktleitungen 4.4.1 420 kV Leitung mit Hohlkörperisolatoren in der Schweiz 4.4.2 Notgestänge mit Verbundisolatoren 4.4.3 Erste 420 kV Doppelleitung mit Volkernverbundtraversen 4.5 Formelzeichen und Abkürzungen 5 Phasenabstandshalter 5.1 Einleitung 5.2 CIGRE Umfrage 5.2.1 Auswertung Fragebogen 5.2.2 Betriebserfahrungen 5.3 Anschlusstechnik 5.4 Mechanische Auslegung von Phasenabstandshaltern 5.4.1 Galloping 5.4.1.1 Galloping Amplituden 5.4.1.2 Bauweisen 5.4.1.3 Einbauempfehlungen 5.4.1.4 Belastungen der PAH durch Galloping 5.4.2 Abwurf von Eislasten 5.4.2.1 Stosskräfte auf die PAH . 5.4.3 Elektrodynamische Kurzschlusskräfte 5.4.4 Das Knickverhalten von Phasenabstandshaltern 5.5 Elektrische Auslegung von Phasenabstandshaltern 5.5.1 Mindestlänge 5.5.2 Koronaeffekte 5.5.3 Verschmutzung 5.6 Anwendungen 5.6.1 Kompaktleitung für Mittelspannung 5.6.2 Phasenabstandshalter gegen Seiltanzen durch Eisabwurf 5.6.3 Der Tennisschlägermast 5.7 Formelzeichen und Abkürzungen 6 Ausblick 7 Anhang IEC Normen betreffend Verbundisolatoren 8 Quellenverzeichnis.

Conceptual design is an early stage in the design process, in which functional requirements of a design problem are transformed into solution concepts for satisfying the requirements. It is regarded as a crucial step in design, because decisions made in this stage will strongly affect all the subsequent stages of the design process. Research evidence suggests that inspiration is useful for exploration and discovery of new solution spaces, and exploration of a wide variety of concepts increases the chances of developing more novel, and hence more creative solutions. There are various approaches to providing inspiration, e.g., creativity techniques such as trigger word technique, biomimetics such as Idea-Inspire, and computational synthesis approaches such as compositional synthesis. Computational synthesis tools are used for automated generation of concepts, which can be offered to the designer as triggers for inspiring ideation. The advantage of using solutions from computational synthesis as triggers are the following: the solutions can be produced in a relatively unbiased manner, allowing a variety of directions to be explored, and the solutions are exhaustive within the constraints of the databases or rules used, allowing a multitude of possibilities to be offered. However, computational synthesis has been traditionally used for automating solution generation, rather than creating triggers for designers’ ideation. Notwithstanding their potential for inspiring ideation, current computational synthesis approaches rarely focused on this task. One exception is FuncSION, a compositional synthesis tool, which can automatically synthesize solution concepts for mechanical devices, where a set of input and output characteristics i.e. functional requirements are provided by the user and the computer generates solutions by combining building blocks from a library to satisfy the requirements; these solutions are then used as stimuli for ideation by designers. The focus of this thesis is on evaluating and improving the effectiveness of computational synthesis in triggering ideation during conceptual design, in terms of improving the fluency and variety of the concept space produced. FuncSION has been used as the example synthesis approach on which the work has been focused. In order to evaluate the effectiveness of FuncSION in terms of fluency and variety, a method for assessing variety of a concept space is proposed, and a tool for supporting the assessment process has been developed. However, compositional synthesis research has always assumed that the building blocks are given, and has confined its focus on the process of combining the building blocks. It has not been investigated as to how such building blocks can be automatically identified. If new building blocks can be automatically identified, the resulting change in the library of building blocks would have a substantial effect on the outcomes of compositional synthesis, i.e. the triggers that can be offered to the designers for ideation, with a resulting effect on the concepts generated by the designers. Therefore, in this thesis, an automated method for building blocks synthesis has been proposed, and has been implemented as a computational tool.

Dissertation (PhD)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: The globalisation is increasing the complexity of product development in terms of product variants and the range of technologies implemented. It emphasises the requirement for developing various design information support systems for the world market. However, small and medium enterprises that employ a wide range of design procedures may not be able to afford customised information support systems, with the result that there is a need for flexible, i.e. easily adaptable, design support tools. Four case studies were carried out to investigate the requirements for an information support system aimed at the design process and design documents. They indicated that a design information support system aimed at supporting design teams in the pre-detail mechanical design phases should be able to adapt various design methods and handle design information in a flexible way. Flexible here means being applicable over a wide range of contexts and extendable without affecting data already captured. Ontology based approaches are widely applied where diverse information has to be handled. The development of the Internet today also makes a distributed design approach more and more popular for mechanical design. An internet-based design support system called DiDeas II (Distributed Design assistant) was developed here with an ontologybased approach implemented to provide distributed and flexible assistance during concept generation in small companies. The DiDeas II has separate server side and client side programs, which communicate through a TCP/IP connection. DiDeas II allows design teams to manage their design information according to various design methods, to decrease time-delays and to improve communication between team members. These benefits were confirmed in two case studies carried out to evaluate DiDeas II. Keywords: Distributed design; ontology; concept design, web-based system. / AFRIKAANSE OPSOMMING: Globalisering verhoog die kompleksiteit van produkontwikkeling, in terme van produk variante en die bereik van tegnologieë wat geïmplementeer word. Dit beklemtoon die behoefte om verskeie ontwerp-inligting-ondersteuningstelsels vir die wêreldmark te ontwikkel. Klein en medium ondernemings wat 'n wye spektrum ontwerpsprosedures gebruik, kan egter nie doelgemaakte inligting-ondersteuningstelsels bekostig nie, met die gevolg dat daar 'n behoefte vir maklik-aanpasbare ontwerp ondersteuningstelsels is. Vier gevallestudies is uitgevoer om die vereistes vir 'n inligting-ondersteuningstelsel gemik op die ontwerpproses en ontwerp dokumente, te ondersoek. Dit het aangetoon dat 'n ontwerp-inligting-ondersteuningstelsel, wat ontwerpspanne in die voor-detail meganiese ontwerp fases moet ondersteun, by verskeie ontwerpmetodes moet kan aanpas en ontwerpsinligting op 'n aanpasbare manier kan hanteer. Aanpasbaarheid in hierdie konteks beteken toepaslik oor 'n wye spektrum kontekste en uitbreibaar sonder om data wat alreeds ingevoer is, te beïnvloed. Ontologie-gebaseerde benaderings word wyd toegepas waar diverse inligting hanteer moet word. Die ontwikkeling van die Internet maak 'n verspreide-ontwerpbenadering meer en meer gewild vir meganiese ontwerp. 'n Internet-gebaseerde ontwerpondersteuningstelstel genaamd DiDeas II (Distributed Design assistant) is hier ontwikkel met 'n ontologie-gebaseerde benadering wat daarop gemik is om verspreide, aanpasbare hulp te verleen aan klein maatskappye gedurende konsep- ontwikkeling. Die DiDeas II stelsel het afsonderlike bediener en kliënt programme wat deur 'n TCP/IP verbinding kommunikeer. DiDeas II laat ontwerpspanne toe om hulle ontwerp inligting volgens verskeie ontwerpmetodes te bestuur, tydvertragings te verminder en om kommunikasie tussen spanlede te verbeter. Hierdie voordele is bevestig in twee gevallestudies wat uitgevoer is om DiDeas II te evalueer. Sleutelwoorde: Verspreide ontwerp; ontologie; konsepontwerp; web-gebaseerde stelsel.

A presente dissertação trata do projeto de um motor de combustão interna de quatro tempos, ciclo Otto, destinado à categoria de competição Formula SAE, adequado ao mercado brasileiro. Uma extensa pesquisa bibliográfica e de mercado foi realizada para o direcionamento do projeto, além de análises experimentais para obtenção de dados. No estudo experimental foi utilizado um motor monocilíndrico de 300 cc de deslocamento volumétrico, arrefecido a ar, oriundo de uma motocicleta comercial atual, denominado nesta dissertação como \"motor base\". Esse motor foi instalado em uma bancada de dinamômetro e instrumentado de forma a permitir sua avaliação mecânica e termodinâmica. Estudos de desempenho, análises de combustão e emissões também foram realizados, incluindo utilização de etanol, variações da razão ar/combustível e sobrealimentação. Igualmente, foram feitos ensaios experimentais de componentes específicos utilizados no projeto. Os dados experimentais foram utilizados como parâmetros para o projeto mecânico do novo motor Formula SAE, e para a modelagem e simulação do motor base em fluidodinâmica computacional unidimensional (CFD-1D), que foi utilizada como ferramenta auxiliar do projeto. O escopo do projeto mecânico do motor foi restrito ao bloco, virabrequim e alguns componentes de integração, uma vez que todos os demais componentes foram extraídos do motor base e de outros motores presentes no mercado nacional. O motor Formula SAE foi projetado em ambiente computacional (CAD), sendo que para o projeto mecânico do bloco e virabrequim foram realizadas simulações computacionais estruturais, utilizando o método dos elementos finitos (FEA), para verificação da distribuição de tensões nos componentes projetados. O novo motor Formula SAE apresentou vantagens significativas em relação aos custos para aquisição de peças de montagem e reposição, e proporcionou flexibilidade de montagem e operação. / The present dissertation addresses the design of a 4 stroke Otto cycle internal combustion engine dedicated to Formula SAE student program and fitted to the Brazilian market. An extensive literature review and a market benchmark were performed, in order to provide guidance to the project, and experimental analysis for data acquisition. For the experimental study, a 300 cm3 single cylinder air cooled motorcycle engine has been used, taken from a motorcycle currently in production, available in Brazilian market, called in this dissertation as \"base engine\". This engine has been installed in a dynamometer test bench and instrumented in order to allow its mechanical and thermodynamic evaluation. Performance, combustion and emissions analysis were also performed, including ethanol fueling, air/fuel ratio variation and supercharging. Experimental tests with specific engine components were performed to provide necessary design data. The experimental data were used as input parameters for the mechanical design, as well as for modeling and simulation of the base engine on one-dimensional computer fluid dynamics, which was used as an auxiliary tool for this project. The scope of mechanical design of this engine was restrict to the crankcase, crankshaft and some assembly components, since all other components were taken from the base engine and other engines from the national market. The design was assisted by computer aided design (CAD). In order to verify the crankcase and crankshaft mechanical design regarding stress distribution, computational structural analysis have been performed using the finite element method (FEA). The new Formula SAE engine presented significant advantages regarding purchasing costs of parts for assembly and maintenance, and provided assembly and operation flexibility.

A moagem e mistura rápidas e efetivas de materiais em pequenos volumes é uma necessidade nos laboratórios e na indústria moderna. Diversos tipos de métodos e equipamentos prestam este serviço, dentre eles o moinho e misturador planetário. Estes equipamentos são máquinas centrífugas que combinam movimentos rotacionais com translacionais e que utilizam os efeitos otimizados das forças, direções e movimentos dos materiais em processo. Para o moinho é otimizado e ampliado o poder dos mecanismos de moagem, sendo então considerado um processo de alta energia. No caso dos misturadores há a combinação do movimento planetário com um ângulo de inclinação entre o eixo de rotação do jarro com o eixo de translação que promovem vórtices helicoidais efetivos para promover a mistura. O presente trabalho objetiva o desenvolvimento de moinho e misturador planetário visando determinar condições otimizadas de moagem e mistura, o estabelecimento de limites de operação para ambas aplicações e a seleção de um sistema de transmissão simplificada. Inicialmente foram fabricados bancos híbridos de moagem e mistura para pequenas amostras (25 g para moagem e 100 g para mistura). O desempenho de moagem foi analisado pela determinação do tamanho de partículas antes e após o processo de moagem em pós de alumina de granulação grosseira com diâmetro médio de partícula em torno de 4,2 μm, variando-se as combinações de relação de transmissão, velocidade de translação e tamanho do meio de moagem. Para o misturador foi aplicado ângulo de inclinação de 30º e realizado ensaios nas misturas de massa plástica em diferentes rotações. Na configuração moinho, o melhor desempenho experimental resultou em pó de alumina submicrométrico de Øee ~ 0,9 mm em uma hora de moagem na rotação de translação de 450 rpm e relação de transmissão eixo principal/jarro de 1:-2. Na configuração misturador a condição otimizada foi com rotação de 2000 rpm e relação transmissão eixo principal/jarro de -2:1 que proporcionou mistura relativamente homogênea em 30 s. Para carregamentos de até 25 g de pós cerâmicos, em que o conjunto excêntrico (jarro, fixação, matéria prima e meios de moagem) são inferiores à 1 kg, utilizou-se a transmissão baseada em rodas de atrito que permitiu um projeto econômico e compacto, sendo o aço (AISI 4340 temperado e revenido) o material da roda de atrito que apresentou a melhor durabilidade e confiabilidade. Entretanto, apresentou limitação na moagem de amostras maiores (jarro acima de 1 kg) e nas misturas com rotações acima de 2000 rpm. A maior potência de transmissão exigida causou aquecimento excessivo na transmissão, ocasionando dilatação das rodas de atrito e consequentemente travamento do sistema. Para aumentar a capacidade de moagem para até 100 g de matéria prima, que reflete a conjuntos com massas superiores a 2 kg, um protótipo utilizando engrenagens foi projetado, construído e testado. Neste trabalho concluiu-se que, através de uma rápida reconfiguração, um único equipamento híbrido atende às ambas demandas. Entretanto observou-se que como as condições otimizadas de moagem e mistura ocorreram em condições opostas, ficou evidenciado que a condição ótima para um sistema, quando aplicado no outro sistema, oferece alto risco de acidentes, o que exige o desenvolvimento de um sistema de segurança inteligente sofisticado e oneroso que, em virtude do agregado financeiro dos componentes permanentes, para aplicações nos processos industriais, aconselha-se equipamentos individuais. / Fast and effective milling and mixing of materials in small volumes is a need for laboratories and modern industry. Several methods and equipment provide these services such as planetary mill and Dual Asymmetric Centrifuge (DAC). These pieces of equipment are centrifuge machines that combine rotation and revolution and use the optimized effects of forces, directions and movements of materials in process. In the mill, the power of the milling mechanisms is optimized, being considered a high-energy process. For the mixers there is a combination of planetary motion and a tilt angle between the axis of rotation of the jar and the revolution axis, which promote effective helical vortices for mixing. The present work aims at the development of planetary mill and mixer aiming to determine optimum grinding and mixing conditions, establishment of operating limits for both applications and transmission selection. Initially hybrid grinding and mixing benches for small samples (25 g for milling and 100 g for mixing) were manufactured. The planetary mill performance was analyzed by determining particle size before and after milling of coarse calcined alumina (initial median particle size of 4.2 mm) by varying combinations of transmission ratio, translation speed and media size. For the mixer, a tilting angle of 30º was applied and tests were performed on the modeling clay mixtures applied at different rotations. For the mill configuration, the optimized design with the best experimental setup resulted in sub micrometric alumina powder (Øee ~ 0.9 mm) in only one hour of milling (revolution of 450 rpm and speed ratio main axis/jar transmission ratio of 1:-2). For the mixer configuration, the optimized condition (revolution of 2000 rpm and speed ratio of -2:1) provided relatively homogeneous mixing in 30 s. For loadings up to 25 g of ceramic powders, where the eccentric assembly (jar, fixing, raw material and grinding media) is lighter than 1kg, the transmission based on friction wheels was used, which allowed an economical and compact design, being the steel (tempered AISI 4340) the material of the friction wheel that presented the best durability and reliability. However, there was a limitation in the grinding of larger samples (jar over 1 kg) and mixtures with rotations above 2000 rpm. The higher transmission power required caused excessive heat in the transmission, causing the friction wheels to dilate and consequently system malfunction. To perform loads greater than 100g of raw material, which reflects sets with masses over 2 kg, a prototype using gears was designed, built and tested. This work concluded that a quick reconfiguration allows a single device meets both demands. However, considering that optimized parameters of grinding and mixing occur at very different conditions, it is emphasizedthat the optimal operation for a system if applied in the optimal conditions of the other system offers high risk of accidents, which requires the development of a costly security system. Therefore, individual pieces of equipment for grinding and mixing are advised for industry application due to the financial aggregate of the permanent components.

Compliant and flexible cardiac catheters provide direct access to the inside of the heart via the vascular system without requiring clinicians to stop the heart or open the chest. However, the fast motion of the intracardiac structures makes it difficult to modify and repair the cardiac tissue in a controlled and safe manner. In addition, rigid robotic tools for beating heart surgery require the chest to be opened and the heart exposed, making the procedures highly invasive. The novel robotic catheter system presented here enables minimally invasive repair on the fast-moving structures inside the heart, like the mitral valve annulus, without the invasiveness or risks of stopped heart procedures. In this thesis, I investigate the development of 3D ultrasound-guided robotic catheters for beating heart surgery. First, the force and stiffness values of tissue structures in the left atrium are measured to develop design requirements for the system. This research shows that a catheter will experience contractile forces of 0.5 – 1.0 N and a mean tissue structure stiffness of approximately 0.1 N/mm while interacting with the mitral valve annulus. Next, this thesis presents the catheter system design, including force sensing, tissue resection, and ablation end effectors. In order to operate inside the beating heart, position and force control systems were developed to compensate for the catheter performance limitations of friction and deadzone backlash and evaluated with ex vivo and in vivo experiments. Through the addition of friction and deadzone compensation terms, the system is able to achieve position tracking with less than 1 mm RMS error and force tracking with 0.08 N RMS error under ultrasound image guidance. Finally, this thesis examines how the robotic catheter system enhances beating heart clinical procedures. Specifically, this system improves resection quality while reducing the forces experienced by the tissue by almost 80% and improves ablation performance by reducing contact resistance variations by 97% while applying a constant force on the moving tissue. / Engineering and Applied Sciences

A moagem e mistura rápidas e efetivas de materiais em pequenos volumes é uma necessidade nos laboratórios e na indústria moderna. Diversos tipos de métodos e equipamentos prestam este serviço, dentre eles o moinho e misturador planetário. Estes equipamentos são máquinas centrífugas que combinam movimentos rotacionais com translacionais e que utilizam os efeitos otimizados das forças, direções e movimentos dos materiais em processo. Para o moinho é otimizado e ampliado o poder dos mecanismos de moagem, sendo então considerado um processo de alta energia. No caso dos misturadores há a combinação do movimento planetário com um ângulo de inclinação entre o eixo de rotação do jarro com o eixo de translação que promovem vórtices helicoidais efetivos para promover a mistura. O presente trabalho objetiva o desenvolvimento de moinho e misturador planetário visando determinar condições otimizadas de moagem e mistura, o estabelecimento de limites de operação para ambas aplicações e a seleção de um sistema de transmissão simplificada. Inicialmente foram fabricados bancos híbridos de moagem e mistura para pequenas amostras (25 g para moagem e 100 g para mistura). O desempenho de moagem foi analisado pela determinação do tamanho de partículas antes e após o processo de moagem em pós de alumina de granulação grosseira com diâmetro médio de partícula em torno de 4,2 μm, variando-se as combinações de relação de transmissão, velocidade de translação e tamanho do meio de moagem. Para o misturador foi aplicado ângulo de inclinação de 30º e realizado ensaios nas misturas de massa plástica em diferentes rotações. Na configuração moinho, o melhor desempenho experimental resultou em pó de alumina submicrométrico de Øee ~ 0,9 mm em uma hora de moagem na rotação de translação de 450 rpm e relação de transmissão eixo principal/jarro de 1:-2. Na configuração misturador a condição otimizada foi com rotação de 2000 rpm e relação transmissão eixo principal/jarro de -2:1 que proporcionou mistura relativamente homogênea em 30 s. Para carregamentos de até 25 g de pós cerâmicos, em que o conjunto excêntrico (jarro, fixação, matéria prima e meios de moagem) são inferiores à 1 kg, utilizou-se a transmissão baseada em rodas de atrito que permitiu um projeto econômico e compacto, sendo o aço (AISI 4340 temperado e revenido) o material da roda de atrito que apresentou a melhor durabilidade e confiabilidade. Entretanto, apresentou limitação na moagem de amostras maiores (jarro acima de 1 kg) e nas misturas com rotações acima de 2000 rpm. A maior potência de transmissão exigida causou aquecimento excessivo na transmissão, ocasionando dilatação das rodas de atrito e consequentemente travamento do sistema. Para aumentar a capacidade de moagem para até 100 g de matéria prima, que reflete a conjuntos com massas superiores a 2 kg, um protótipo utilizando engrenagens foi projetado, construído e testado. Neste trabalho concluiu-se que, através de uma rápida reconfiguração, um único equipamento híbrido atende às ambas demandas. Entretanto observou-se que como as condições otimizadas de moagem e mistura ocorreram em condições opostas, ficou evidenciado que a condição ótima para um sistema, quando aplicado no outro sistema, oferece alto risco de acidentes, o que exige o desenvolvimento de um sistema de segurança inteligente sofisticado e oneroso que, em virtude do agregado financeiro dos componentes permanentes, para aplicações nos processos industriais, aconselha-se equipamentos individuais. / Fast and effective milling and mixing of materials in small volumes is a need for laboratories and modern industry. Several methods and equipment provide these services such as planetary mill and Dual Asymmetric Centrifuge (DAC). These pieces of equipment are centrifuge machines that combine rotation and revolution and use the optimized effects of forces, directions and movements of materials in process. In the mill, the power of the milling mechanisms is optimized, being considered a high-energy process. For the mixers there is a combination of planetary motion and a tilt angle between the axis of rotation of the jar and the revolution axis, which promote effective helical vortices for mixing. The present work aims at the development of planetary mill and mixer aiming to determine optimum grinding and mixing conditions, establishment of operating limits for both applications and transmission selection. Initially hybrid grinding and mixing benches for small samples (25 g for milling and 100 g for mixing) were manufactured. The planetary mill performance was analyzed by determining particle size before and after milling of coarse calcined alumina (initial median particle size of 4.2 mm) by varying combinations of transmission ratio, translation speed and media size. For the mixer, a tilting angle of 30º was applied and tests were performed on the modeling clay mixtures applied at different rotations. For the mill configuration, the optimized design with the best experimental setup resulted in sub micrometric alumina powder (Øee ~ 0.9 mm) in only one hour of milling (revolution of 450 rpm and speed ratio main axis/jar transmission ratio of 1:-2). For the mixer configuration, the optimized condition (revolution of 2000 rpm and speed ratio of -2:1) provided relatively homogeneous mixing in 30 s. For loadings up to 25 g of ceramic powders, where the eccentric assembly (jar, fixing, raw material and grinding media) is lighter than 1kg, the transmission based on friction wheels was used, which allowed an economical and compact design, being the steel (tempered AISI 4340) the material of the friction wheel that presented the best durability and reliability. However, there was a limitation in the grinding of larger samples (jar over 1 kg) and mixtures with rotations above 2000 rpm. The higher transmission power required caused excessive heat in the transmission, causing the friction wheels to dilate and consequently system malfunction. To perform loads greater than 100g of raw material, which reflects sets with masses over 2 kg, a prototype using gears was designed, built and tested. This work concluded that a quick reconfiguration allows a single device meets both demands. However, considering that optimized parameters of grinding and mixing occur at very different conditions, it is emphasizedthat the optimal operation for a system if applied in the optimal conditions of the other system offers high risk of accidents, which requires the development of a costly security system. Therefore, individual pieces of equipment for grinding and mixing are advised for industry application due to the financial aggregate of the permanent components.

A presente dissertação trata do projeto de um motor de combustão interna de quatro tempos, ciclo Otto, destinado à categoria de competição Formula SAE, adequado ao mercado brasileiro. Uma extensa pesquisa bibliográfica e de mercado foi realizada para o direcionamento do projeto, além de análises experimentais para obtenção de dados. No estudo experimental foi utilizado um motor monocilíndrico de 300 cc de deslocamento volumétrico, arrefecido a ar, oriundo de uma motocicleta comercial atual, denominado nesta dissertação como \"motor base\". Esse motor foi instalado em uma bancada de dinamômetro e instrumentado de forma a permitir sua avaliação mecânica e termodinâmica. Estudos de desempenho, análises de combustão e emissões também foram realizados, incluindo utilização de etanol, variações da razão ar/combustível e sobrealimentação. Igualmente, foram feitos ensaios experimentais de componentes específicos utilizados no projeto. Os dados experimentais foram utilizados como parâmetros para o projeto mecânico do novo motor Formula SAE, e para a modelagem e simulação do motor base em fluidodinâmica computacional unidimensional (CFD-1D), que foi utilizada como ferramenta auxiliar do projeto. O escopo do projeto mecânico do motor foi restrito ao bloco, virabrequim e alguns componentes de integração, uma vez que todos os demais componentes foram extraídos do motor base e de outros motores presentes no mercado nacional. O motor Formula SAE foi projetado em ambiente computacional (CAD), sendo que para o projeto mecânico do bloco e virabrequim foram realizadas simulações computacionais estruturais, utilizando o método dos elementos finitos (FEA), para verificação da distribuição de tensões nos componentes projetados. O novo motor Formula SAE apresentou vantagens significativas em relação aos custos para aquisição de peças de montagem e reposição, e proporcionou flexibilidade de montagem e operação. / The present dissertation addresses the design of a 4 stroke Otto cycle internal combustion engine dedicated to Formula SAE student program and fitted to the Brazilian market. An extensive literature review and a market benchmark were performed, in order to provide guidance to the project, and experimental analysis for data acquisition. For the experimental study, a 300 cm3 single cylinder air cooled motorcycle engine has been used, taken from a motorcycle currently in production, available in Brazilian market, called in this dissertation as \"base engine\". This engine has been installed in a dynamometer test bench and instrumented in order to allow its mechanical and thermodynamic evaluation. Performance, combustion and emissions analysis were also performed, including ethanol fueling, air/fuel ratio variation and supercharging. Experimental tests with specific engine components were performed to provide necessary design data. The experimental data were used as input parameters for the mechanical design, as well as for modeling and simulation of the base engine on one-dimensional computer fluid dynamics, which was used as an auxiliary tool for this project. The scope of mechanical design of this engine was restrict to the crankcase, crankshaft and some assembly components, since all other components were taken from the base engine and other engines from the national market. The design was assisted by computer aided design (CAD). In order to verify the crankcase and crankshaft mechanical design regarding stress distribution, computational structural analysis have been performed using the finite element method (FEA). The new Formula SAE engine presented significant advantages regarding purchasing costs of parts for assembly and maintenance, and provided assembly and operation flexibility.

La recherche d’une locomotion performante sur des terrains accidentés constitue encore à l’heure actuelle un défi pour les systèmes robotisés de toutes sortes s’y attelant. Les robots hybrides de type “roues-pattes”, qui tentent d’allier l’efficacité énergétique des roues à l’agilité des pattes, en sont un exemple aux capacités potentiellement très prometteuses. Malheureusement, le contrôle de telles structures s’avère rapidement problématique du fait des redondances cinématiques, mais aussi et surtout de la difficulté que pose la connaissance exacte de la géométrie du sol à mesure que le robot avance. Cette thèse propose alors une réponse à la complexité des systèmes roulants reconfigurables par une approche synergique entre compliance et actionnement. Pour cela, nous proposons d’exploiter une décomposition idéalement orthogonale entre les différentes formes de compliances qui réalisent la suspension du robot. Ainsi, l’actionnement au sein de la structure est ici dédié à un contrôle des efforts verticaux s’exerçant sur les roues, tandis que les déplacements horizontaux de ces dernières sont le fait d’une raideur passive combinée à une modulation locale des vitesses d’entraînement. La posture du robot est maîtrisée via l’asservissement des forces verticales fournies par un actionnement de type série-élastique. Ceci permet de garantir une adaptation spontanée de la hauteur des roues tout en conservant l’ascendant sur la distribution de la charge. La faisabilité d’un tel système de locomotion est validée à travers un prototype reposant sur quatre “roues-pattes” compliantes. Celui-ci, entièrement conçu dans le cadre de cette étude, approche la décomposition fonctionnelle proposée tout en répondant aux contraintes de réalisation et de robustesse. Tirant parti de la décomposition fonctionnelle proposée pour la structure, deux procédés de commande sont présentés afin de réaliser le franchissement des obstacles : le premier vise à exploiter l’inertie du châssis pour réaliser une modification locale des forces verticales appliquées aux roues, tandis que le second est basé sur la sélection d’un mode de répartition des efforts adaptés à la poursuite d’une évolution quasi-statique en toutes circonstances. Pour cette dernière commande, deux méthodes de synthèse sont abordées : l’une via un algorithme d’apprentissage de type “Q-learning” et l’autre par détermination de règles expertes paramétrées. Ces commandes, validées par des simulations dynamiques dans des situations variées, se basent exclusivement sur des données proprioceptives accessibles immédiatement par la mesure des variables articulaires de la structure. De cette manière, le robot réagit directement au contact des obstacles, sans avoir besoin de connaître à l’avance la géométrie du sol. / Performing an efficient locomotion on rough terrains is still a challenge for robotic systems of all kinds. “Wheel-on-leg” robots that try to combine energy efficiency of wheels with leg agility are an example with potentially very promising capabilities. Unfortunately, control of such structures turns out to be problematic because of the kinematic redundanciesand, above all, the difficulty of precisely evaluating the ground geometry as the robot advances. This thesis proposes a solution to the complexity of reconfigurable rolling systems by a synergic approach between compliance and actuation.To this purpose, we propose to exploit an ideally orthogonal decomposition between the different movements enabled by the robot suspension due to compliant elements. Then, the structure actuation is here dedicated to controlling the vertical forces applied on wheels, while the horizontal wheel displacements are due to a passive stiffness combined with a local modulation of wheel speed. The robot posture is controlled through the vertical forces servoing provided by a series elastic actuation. This ensures a spontaneous adaptation of wheel heights while keeping the control on load distribution. The feasibility of such a locomotion system is validated through a prototype based on four compliant “wheel-legs”. Entirely conceived as part of this study, this one approximates the proposed functional decomposition while meeting the realization and robustness constraints. We also present two control methods that take advantage of the functional decompositionproposed for the structure in order to cross obstacles. The first one aims to exploit the chassis inertia in order to perform a local modification of the vertical forces applied on wheels, while the second one is based on the selection of proper ways of distributing forces in order to be able to pursue a quasi-static advance in all circumstances. Two approaches are given for the production of the last control : either with a “Q-learning” algorithm or by determining parameterized expert rules. Validated by dynamic simulations in various situations, these controls rely only on proprioceptive data immediately provided by the measurement of articular variables. This way, the robot directly reacts when it touches obstacles, without having to know the ground geometry in advance.